Re: K+ overdose-electrolytes

[Sue Brown <sbrown@wamedes.com>]

>>i was trying new stuff on me back on the od100 one year- i had this great
idea to take extra K potassium.. to help the ticker manage the climbs - i
ran more back in those daysbut if anyone has unknown problems, it could be
disasterous. " Over doses of K+ kill... ie is also what is used for lethal
injections. When the K+ is too low or too high, the tissues of the heart
cannot work properly and that is one cause of a lethal heart attack. 


I'll second that!  The solution that we use in open heart surgery (called
cardioplegia) is a high potassium IV that we infuse into the heart itself
after we go on bypass and clamp the heart off from the rest of the body.
It stops the heart in a flash...and it *has* to since we have to cut down
the oxygen consumption of the heart immediately to do it no harm.  At the
end of whatever we're doing to the heart, we take the clamp off and let the
heart reperfuse (and the potassium go to the rest of the body) and then
sock the patient with Lasix so that they pee out the potassium.  When
enough potassium has left the heart, the heart starts back up.  If they
have kidney problems, it's a bit dicier and there's a bit different
procedure...but, the crux is, severely high potassium stops the heart cold.
 Moderately high potassium sets the heart up for fibrillation with any
stress to the myocardium.  They run potassium levels frequently after the
aortic crossclamp is off to make sure that the body is excreting it
sufficiently...and they don't come off bypass until they know that the
heart is safe.  

On the other end of the spectrum, they won't give a patient anesthesia if
the potassium is too low because the onset of anesthesia (general) is
enough to send the heart into fibrillation.  The problem with fibrillation
caused by wacky potassiums is that if you get the heart to beat regularly,
it's probably going to flip back into fibrillation if the potassium isn't
corrected ASAP.  And then there's the problem of intercellular potassium vs
intravascular potassium...ie...you can't inject potassium into the
bloodstream and have it immediately take affect in the firing part of the
cells because it has to circulate around and then fudge it's way into the
cells.  This takes time.  It also takes time to squeeze excess potassium
out of the bloodstream and the cells if they get too much...so you can get
it deep trouble and there isn't a "quick fix" -- in a human it would
involve cardiodefibrillation and the CPR until the potassium level is
corrected.  In a horse, you're sorta SOL.

Sue (who just...at 8pm...got home from the clinic to find out I have to be
at the hospital by 6am to do a re-do CABG (coronary bypass)...and I'd
rather go riding cuz Aarene's off and, and...!!! ;-)  However, I still have
more tack to buy! :-p)

sbrown@wamedes.com
Tyee Farm
Marysville, Wa.


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